The present invention relates to a word information storage and retrieval device and, more particularly, to a letter input device for a word information storage and retrieval device such as an electronic dictionary.
A conventional letter input device for a word information storage and retrieval device such as an electronic dictionary comprises a keyboard including a plurality of key switches each corresponding to each letter. Each of the key switches is actuated to input a specific letter. However, this input system has required a rather wide keyboard including the plurality of key switches. Although it is desirable that an electronic apparatus such as an electronic dictionary be as compact as possible, it has been difficult to miniaturize the size of the keyboard in view of the manual operations. Alternatively, it has been proposed that the electronic dictionaries utilize keyboards having a reduced number of key switches selected from the plurality of key switches of the keyboard actuated to input a great number of letters. However, the key input of such an input device is rather complicated and requires a long time to input a word having a large number of letters.
Therefore, it is desired that a compact letter input device be provided for inputting a word having a large number of letters in a short period of time.